Currently, for receiving notebooks, or communication devices or other portable electronic devices, bags are made of hard materials so as to protect the objects receiving therein.
In these kinds of bags, the upper sides of the bags have an opening and a cover is installed for covering the opening. The operation is performed by tightening one or two bands protruded from a front surface of the bag and then the bands are buckled to the buckles at the front surface. However, this prior art fixing way only fixes the front surface, but two sides of the bag are not fixed, and also they are opened at two sides so that objects in the bag possibly fall out from the opened sides.